Armstrong Siddeley Cheetah

The Armstrong Siddeley Cheetah is a seven-cylinder British air-cooled aircraft radial engine of 834 cu in (13.65 L) capacity introduced in 1935 and produced until 1948. Early variants of the Cheetah were initially known as the Lynx Major.

The Cheetah was used to power many British trainer aircraft during World War II including the Avro Anson and Airspeed Oxford.

Design and development

The Cheetah was developed from the earlier Lynx using the increased bore cylinders from the Armstrong Siddeley Panther but the engine retained the stroke of the Lynx. Initially only direct-drive variants were produced with later engines being made available with propeller reduction gear of various ratios. Superchargers were also available for later variants, both geared and directly driven by the crankshaft.

The basic design of the Cheetah remained unchanged from its introduction in 1935 to the last examples built in 1948. It was the first engine of its type to be certified for 1,200 hours of operational time between overhauls, with over 37,200 examples built.

Variants

List from: LumsdenNote:

Lynx V (Lynx Major)

1930, 230 hp (171 kW).

Cheetah V

1935, 270 hp (201 kW) at 2,100 rpm.

Cheetah VA

1935, 285 hp (212 kW) at 2,425 rpm.

Cheetah VI

1935, 307 hp (229 kW) at 2,425 rpm.

Cheetah VIA

1936, as Mk VI but with Mk IX cylinders.

File:Armstrong Siddeley Cheetah Mk.X.JPG

Preserved Cheetah X

Cheetah IX

1937, 345 hp (257 kW) at 2,425 rpm.

Cheetah X

1938, 375 hp (280 kW) at 2,300 rpm.

Cheetah XI

345 hp (257 kW) at 2,425 rpm, geared version of Cheetah X.

Cheetah XII

Similar to Mk X, adapted for target drone aircraft.

Cheetah XV

420 hp (313 kW) at 2,425 rpm.

Cheetah XVII

1948, 385 hp (287 kW) at 2,425 rpm.

Cheetah XVIII

385 hp (287 kW) at 2,425 rpm, carburettor modified for aerobatics.

Cheetah XIX

355 hp (265 kW) at 2,425 rpm

Cheetah 25

345 hp (257 kW) at 2,425 rpm, Cheetah XV uprated to 475 hp (355 kW) at 2,700 rpm, modified constant-speed unit.

Cheetah 26

385 hp (287 kW).

Cheetah 27

1948, 385 hp (287 kW).

Applications

• Airspeed Consul
• Airspeed Courier
• Airspeed Envoy
• Airspeed Oxford
• Airspeed Queen Wasp
• Airspeed Viceroy
• Avro 626
• Avro 652
• Avro Anson
• Blackburn Lincock
• Bristol Bulldog

File:Avro Prefect.jpg

Avro 626 Prefect

• CASA C-201 Alcotán
• de Havilland Hawk Moth
• Edgar Percival Prospector
• Handley Page H.P.R.2
• Hispano HS-42
• IAe.22 DL
• Koolhoven F.K.51
• Marinens Flyvebaatfabrikk M.F.8
• Marinens Flyvebaatfabrikk M.F.10
• Percival Provost (prototype)

Survivors

As of October 2008 at least four Cheetah engines remained airworthy. Two Cheetah 17s power the Anson T21 operated by the Air Atlantique Classic Flight and another pair of Cheetah 17s are fitted to Avro Nineteen, G-AHKX registered to BAE Systems but normally based at the Shuttleworth Collection.

Specifications (Cheetah IX)

File:Armstrong Siddeley Cheetah(Oxford)01.jpg

Cheetah engine fitted to an Airspeed Oxford undergoing restoration

See also

Related development

• Armstrong Siddeley Lynx
• Armstrong Siddeley Panther

Related lists

• List of aircraft engines

References

Bibliography

• Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9
• Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. ISBN 1-85310-294-6.

Further reading

• Bridgman, L, (ed.) (1998). Jane's fighting aircraft of World War II.. Crescent. ISBN 978-0-517-67964-7. 
• Gunston, Bill. Development of Piston Aero Engines. Cambridge, England. Patrick Stephens Limited, 2006. ISBN 0-7509-4478-1

External links

Wikimedia Commons has media related to:

Armstrong Siddeley Cheetah

• Flight magazine, 19 May 1939 - Introduction of the Cheetah X - Flightglobal.com

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Armstrong Siddeley Cheetah".